Circulating interleukin (IL)‐6 and IL‐10 concentrations are widely used to evaluate the anti‐inflammatory effects of exercise but do not capture cytokine action at the cellular level. Whether and how acute exercise impacts anti‐inflammatory cytokine action in humans is unknown. To determine how exercise intensity and pattern impact IL‐6 and IL‐10 action in blood leukocytes, 16 active adults (eight males/eight females; age: 30 ± 3 years; body mass index: 22.8 ± 2.3 kg/m²; : 51 ± 6 mL/kg/min) completed a no‐exercise control condition (CTL) or isocaloric bouts of cycling performed below (moderate continuous exercise; MCE) or above (heavy continuous or heavy intermittent exercise; HCE or HIE, respectively) lactate threshold. Venous blood (before, after, 30 min after and 90 min after exercise) was analysed for immune cell subpopulations, plasma cytokine concentrations, anti‐inflammatory cytokine action and monocyte phenotype. Exercise induced rapid leukocytosis (P < 0.001) and increased plasma IL‐6 (P < 0.001), IL‐10 (P = 0.0145) and tumour necrosis factor‐⍺ (TNF‐⍺) (P = 0.0338) concentrations in an intensity‐dependent manner (HCE and/or HIE vs. CTL). These systemic changes coincided with a diminished ability of IL‐10/6 to phosphorylate STAT3 (P < 0.001) and inhibit TNF‐⍺ secretion (P = 0.0238) in blood leukocytes following HCE and HIE. Monocyte polarization experiments revealed lower CD80 [MCE (P = 0.0933) and HIE (P = 0.0187) vs. CTL] and a tendency for higher CD163 expression (HCE vs. CTL, P = 0.0985), suggesting that hyporesponsiveness to anti‐inflammatory cytokine action does not impede the ability of exercise to promote an anti‐inflammatory monocyte phenotype. These findings provide novel insights into the immunomodulatory effects of exercise in humans and highlight the importance of directly measuring cellular cytokine action when evaluating the anti‐inflammatory effects of exercise. image Key points: Circulating cytokine concentrations are frequently used to evaluate the anti‐inflammatory effects of exercise but may not capture changes in cytokine action occurring at the cellular level. We directly assessed anti‐inflammatory cytokine action – measured using a combination of intracellular signalling and cytokine secretion ex vivo – in distinct immune cell subpopulations after acute calorie‐matched exercise bouts differing in intensity and pattern. Anti‐inflammatory cytokine action was blunted following higher intensity exercise despite corresponding increases in circulating cytokine concentrations and immune cell counts. Changes in cytokine action were not explained by changes in cytokine receptor expression on circulating immune cells. Our findings provide new insights into the immunomodulatory effects of exercise in humans and highlight the importance of directly measuring cellular cytokine action when evaluating the anti‐inflammatory effects of exercise.

Nutritional ergogenic aids are commonly used to boost physiological adaptations to exercise and promote greater fitness gains. However, there is a paucity of data about multi-ingredient pre-workout supplementation (MIPS). Therefore, the aim of the present study was to investigate the acute effects of MIPS on the oxidative, glycolytic and ATP-CP energy systems contribution, time spent above 90% V̇O2max (T90% V̇O2max), excess post-exercise oxygen consumption (EPOC) magnitude, number of efforts and time to exhaustion during a high-intensity interval exercise (HIIE) session. Twelve physically-active and healthy men completed the HIIE sessions that involved running bouts of 15 s on the treadmill at 120% of the maximum aerobic speed (MAS), interspersed with 15 s of passive recovery. Blood lactate was collected at immediately post, 3, 5, and 7 min post exercise. The contribution of ATP-CP, glycolytic and oxidative systems was analyzed at rest, during the HIIE sessions and for 20 min post. Performance variables (time to exhaustion, number of efforts) and oxygen consumption were also analyzed. MIPS significantly increased the number of efforts performed (MIPS: 41 ± 10 vs Placebo: 36 ± 12, p = 0.0220) and time to exhaustion (MIPS: 20.1 ± 6 min vs Placebo: 17 ± 5 min, p = 0.0226). There was no difference between supplements for both T90% V̇O2max (p = 0.9705) and EPOC (p = 0.4930). Consuming MIPS significantly increased the absolute oxidative energy system contribution by 23.8% (p = 0.0163) and the absolute ATP-CP contribution by 28.4% (p = 0.0055) compared to placebo. There was only a non-significant tendency for a higher glycolytic system contribution after MIPS ingestion (p = 0.0683). Acute MIPS ingestion appears effective at increasing both aerobic and anaerobic alactic energy contribution and time to exhaustion during a HIIE protocol.